Three dynamically distinct stellar populations in the halo of M49

Abstract

M49 (NGC 4472) is the dominant galaxy in subcluster B of the Virgo Cluster, and a benchmark for studying the build-up of the extended halos of brightest group galaxies in the outskirts of galaxy clusters. We investigate the kinematics in the outer halo of M49, look for substructures, and describe the transition to the surrounding intra-group light. As kinematic tracers we use planetary nebulae (PNe), combining kinematics from the extended Planetary Nebula Spectrograph (PN.S) early-type galaxy survey with our recent deep photometric sample. We study the position-velocity-plane for bright and faint PN populations out to 95 kpc radius, and employ a multi-Gaussian model for the velocity distribution to identify stellar populations with distinct kinematics and histories. We report the detection of stellar-kinematic substructure associated with the interaction of M49 with the dwarf irregular galaxy VCC 1249. We find two kinematically distinct PN populations associated with the main M49 halo and the extended intra-group light (IGL). These have velocity dispersions ${\sigma }_{halo}\simeq 170$ km/s and ${\sigma }_{IGL}\simeq 400$ km/s at 10-80 kpc radii. The overall luminosity profile and velocity dispersion at $\sim 80$ kpc are consistent with a flat circular velocity curve extrapolated from X-ray observations. The dispersion of the PNe associated with the IGL joins onto that of the satellite galaxies in subcluster B at $\sim 100$ kpc radius. This is the first time that the transition from halo to IGL is observed based on the velocities of individual stars. Therefore the halo of M49, consisting of at least three distinct components, has undergone an extended accretion history within its parent group potential. The blue colours of the IGL component are consistent with a population of stars formed in low-mass galaxies at redshift $\sim 0.5$ that has since evolved passively, as suggested by other data.

arXiv comment10 pages, 7 figures, accepted for publication in Astronomy & Astrophysics

References in corpus (71)

• Astropy: A Community Python Package for Astronomy
• emcee: The MCMC Hammer
• The NumPy array: a structure for efficient numerical computation
• Stellar population synthesis at the resolution of 2003
• Tracing Galaxy Formation with Stellar Halos I: Methods
• Structure and Formation of Elliptical and Spheroidal Galaxies
• The Two Phases of Galaxy Formation
• The Universal Stellar Mass-Stellar Metallicity Relation for Dwarf Galaxies
• Subaru Prime Focus Camera -- Suprime-Cam --
• A Method for Measuring (Slopes of) the Mass Profiles of Dwarf Spheroidal Galaxies
• The Frontier Fields: Survey Design
• The ACS Fornax Cluster Survey. V. Measurement and Recalibration of Surface Brightness Fluctuations and a Precise Value of the Fornax--Virgo Relative Distance
• Structure and Kinematics of Early-Type Galaxies from Integral-Field Spectroscopy
• The stellar mass assembly of galaxies in the Illustris simulation: growth by mergers and the spatial distribution of accreted stars
• The SAURON project - III. Integral-field absorption-line kinematics of 48 elliptical and lenticular galaxies
• The ACS Virgo Cluster Survey IX: The Color Distributions of Globular Cluster Systems in Early-Type Galaxies
• The cosmological size and velocity dispersion evolution of massive early-type galaxies
• Post-Asymptotic Giant Branch Evolution of Low- and Intermediate-Mass Stars. Preliminary Results
• New models for the evolution of Post-Asymptotic Giant Branch stars and Central Stars of Planetary Nebulae
• The Hierarchical Origin of Galaxy Morphologies
• Kinematic properties of early-type galaxy haloes using planetary nebulae
• The MASSIVE Survey - I. A Volume-Limited Integral-Field Spectroscopic Study of the Most Massive Early-Type Galaxies within 108 Mpc
• Dark Matter Cores and Cusps: The Case of Multiple Stellar Populations in Dwarf Spheroidals
• Dynamics of the Globular Cluster System Associated with M49 (NGC4472): Cluster Orbital Properties and the Distribution of Dark Matter
• The Burrell Schmidt Deep Virgo Survey: Tidal Debris, Galaxy Halos, and Diffuse Intracluster Light in the Virgo Cluster
• Contributions to the accreted stellar halo: an atlas of stellar deposition
• The Extended Virgo Cluster Catalog
• Intracluster Planetary Nebulae in Virgo: Photometric selection, spectroscopic validation and cluster depth
• Stellar velocity profiles and line strengths out to four effective radii in the early-type galaxies NGC 3379 and NGC 821
• Intracluster Light at the Frontier II: The Frontier Fields Clusters
• Diffuse Tidal Structures in the Halos of Virgo Ellipticals
• Determination of the Dark Matter Profile of Abell 2199 from Integrated Starlight
• The origin of the Milky Way globular clusters
• Modeling the Formation of Globular Cluster Systems in the Virgo Cluster
• Characterizing Diffused Stellar Light in simulated galaxy clusters
• Stellar Absorption Line Analysis of Local Star-Forming Galaxies: The Relation Between Stellar Mass, Metallicity, Dust Attenuation and Star Formation Rate
• The PN.S Elliptical Galaxy Survey: Data Reduction, Planetary Nebula Catalog, and Basic Dynamics for NGC 3379
• The MASSIVE Survey - V. Spatially-Resolved Stellar Angular Momentum, Velocity Dispersion, and Higher Moments of the 41 Most Massive Local Early-Type Galaxies
• Narrow band imaging in [OIII] and Halpha to search for ICPNe in the Virgo cluster
• The Metallicity Distribution of Intracluster Stars in Virgo
• Lost but not Forgotten: Intracluster Light in Galaxy Groups and Clusters
• The Phase-Space Parameters of Brightest Halo Galaxies
• The Planetary Nebulae Spectrograph: the green light for Galaxy Kinematics
• Stellar Populations of Dwarf Elliptical Galaxies: UBVRI Photometry of Dwarf Elliptical Galaxies in the Virgo Cluster
• VEGAS: A VST Early-type GAlaxy Survey. I. Presentation, wide-field surface photometry, and substructures in NGC 4472
• Detection of Intracluster Planetary Nebulae in the Coma Cluster
• The Cluster Velocity Dispersion of the Abell 2199 cD Halo of NGC 6166
• VEGAS: A VST Early-type GAlaxy Survey. II. Photometric study of giant ellipticals and their stellar halos
• Characterizing Intra-cluster light in the Hubble Frontier Fields
• A tale of two tails and an off-centered envelope: diffuse light around the cD galaxy NGC 3311 in the Hydra I cluster
• Discrete dynamical modelling of omega Centauri
• The build-up of the cD halo of M87 - evidence for accretion in the last Gyr
• The planetary nebula population in the halo of M87
• The MASSIVE Survey - VIII. Stellar Velocity Dispersion Profiles and Environmental Dependence of Early-Type Galaxies
• Stripped gas as fuel for newly formed HII regions in the encounter between VCC1249 and M49: a unified picture from NGVS and GUViCS
• The Planetary Nebula Luminosity Function: Pieces of the Puzzle
• The outer regions of the giant Virgo galaxy M87. Kinematic separation of stellar halo and intracluster light
• The unmixed kinematics and origins of diffuse stellar light in the core of the Hydra I cluster (Abell 1060)
• Resolving the Disc-Halo Degeneracy I: A Look at NGC 628
• Steepening mass profiles, dark matter and environment of X-ray bright elliptical galaxies
• Stellar Populations in the Outer Halo of the Massive Elliptical M49
• Integral-field kinematics and stellar populations of early-type galaxies out to three half-light radii
• Kinematic evidence for different Planetary Nebulae Populations in the elliptical galaxy NGC 4697
• The Grism Lens-Amplified Survey from Space (GLASS). IX. The dual origin of low-mass cluster galaxies as revealed by new structural analyses
• Dynamical Models of Elliptical Galaxies -- II. M87 and its Globular Clusters
• Sloshing in its cD halo: MUSE kinematics of the central galaxy NGC 3311
• Counter-dispersed slitless-spectroscopy technique: planetary nebula velocities in the halo of NGC 1399
• The halo of M49 and its environment as traced by planetary nebulae
• The SLUGGS Survey: The Assembly Histories of Individual Early-type Galaxies
• Galaxies with Shells in the Illustris Simulation: Metallicity Signatures
• Intracluster Planetary Nebulae in the Hydra I cluster

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• The Outer Stellar Halos of Galaxies: how Radial Merger Mass Deposition, Shells and Streams depend on Infall-Orbit Configurations
• Structure of Brightest Cluster Galaxies and Intracluster Light
• The Fornax Deep Survey with VST. VIII. Connecting the accretion history with the cluster density
• The extended Planetary Nebula Spectrograph (ePN.S) early-type galaxy survey. The kinematic diversity of stellar halos and the relation between halo transition scale and stellar mass
• The Fornax3D project: Tracing the assembly history of the cluster from the kinematic and line-strength maps
• The stellar halos of ETGs in the IllustrisTNG simulations: the photometric and kinematic diversity of galaxies at large radii
• Clocking the formation of today's largest galaxies: Wide field integral spectroscopy of Brightest Cluster Galaxies and their surroundings
• The MASSIVE Survey - XII Connecting Stellar Populations of Early-Type Galaxies to Kinematics and Environment
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• The survey of planetary nebulae in Andromeda (M31). IV. Radial oxygen and argon abundance gradients of the thin and thicker disc
• The Fornax Cluster VLT Spectroscopic Survey III -- Kinematical characterisation of globular clusters across the Fornax galaxy cluster
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• The halo of M105 and its group environment as traced by planetary nebula populations: I. Wide-field photometric survey of planetary nebulae in the Leo I group
• The halo of M105 and its group environment as traced by planetary nebula populations: II. Using kinematics of single stars to unveil the presence of intragroup light around the Leo I galaxies NGC 3384 and M105
• The Fornax3D project: The assembly history of massive early-type galaxies in the Fornax cluster from deep imaging and integral field spectroscopy
• On the assembly history of massive galaxies. A pilot project with VEGAS deep imaging and M3G integral field spectroscopy
• The Fornax Cluster VLT Spectroscopic Survey IV -- Cold kinematical substructures in the Fornax core from COSTA
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• Investigating the Dark Matter Halo of NGC 5128 using a Discrete Dynamical Model
• Fresh Insights on the Kinematics of M49's Globular Cluster System with MMT/Hectospec Spectroscopy
• The Next Generation Virgo Cluster Survey. XVII. A Search for Planetary Nebulae in Virgo Cluster Globular Clusters
• Planetary Nebulae and How to Find Them: Color Identification in Big Broadband Surveys
• The survey of Planetary Nebulae in Andromeda (M31): I. Imaging the disk and halo with MegaCam@CFHT
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